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Toshiba 20AR21 Service Manual
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Toshiba 20AR21 Service Manual

Toshiba color television service manual
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TOSHIBA
FILE NO.050-200118

SERVICE MANUAL

COLOR TELEVISION
20AR21
20AR31
MT S ST ER EO
AUT O V OL T AGE
AUT O V OL T AGE
DOCUMENT CREATED IN JAPAN, OCT., 2001

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Summary of Contents for Toshiba 20AR21

  • Page 1: Service Manual

    TOSHIBA FILE NO.050-200118 SERVICE MANUAL COLOR TELEVISION 20AR21 20AR31 MT S ST ER EO AUT O V OL T AGE AUT O V OL T AGE DOCUMENT CREATED IN JAPAN, OCT., 2001...

  • Page 2: Table Of Contents

    CATV Channels ............1 thru 125 Color Sub-Carrier Frequency ........42.17 MHz (Nominal) AUDIO POWER Specifications are subject to change without OUTPUT RATING 20AR21 ........1.5 + 1.5 W (at 10% distortion) prior notice. 20AR31 ........3.0 + 3.0 W (at 10% distortion)

  • Page 3: Important Service Safety Precaution

    20AR21 20AR31 IMPORTANT SERVICE SAFETY PRECAUTION Ë Service work should be performed only by qualified service technicians who are thoroughly familiar with all safety checks and the servicing guidelines which follow: WARNING X-RADIATION AND HIGH VOLTAGE LIMITS 1. For continued safety, no modification of any circuit 1.

  • Page 4: Safety Notice

    20AR21 20AR31 IMPORTANT SERVICE SAFETY PRECAUTION (Continued) BEFORE RETURNING THE RECEIVER Connect the resistor connection to all exposed metal parts having a return to the chassis (antenna, metal (Fire & Shock Hazard) cabinet, screw heads, knobs and control shafts, escutcheon and etc.) and measure the AC voltage Before returning the receiver to the user, perform drop across the resistor.

  • Page 5: Location Of User's Control

    20AR21 20AR31 LOCATION OF USER'S CONTROL Front Panel (20AR21) VIDEO/AUDIO TERMINALS (VIDEO/AUDIO terminals are also provided on the rear.) (20AR31) MT S S T ER EO AUT O V OL T AGE VIDEO/AUDIO TERMINALS POWER Press Press again Off. CHANNEL UP/DOWN ( ) Selects next higher channel.

  • Page 6: Installation And Service Instructions

    20AR21 20AR31 INSTALLATION AND SERVICE INSTRUCTIONS Note: (1) When performing any adjustments to resistor controls and transformers use non-metallic screwdrivers or TV alignment tools. (2) Before performing adjustments, the TV set must be on at least 15 minutes. HIGH VOLTAGE CHECK CIRCUIT PROTECTION The receiver is protected by a 3.15A fuse (F701),...
  • Page 7 20AR21 20AR31 For adjustments of this model, the bus data is converted to various analog signals by the D/A converter circuit. Note: There are still a few analog adjustments in this series such as focus and master screen voltage. Follow the steps below whenever the service adjustment is required. See "Table-B" to determine, if serv- ice adjustments are required.

  • Page 8: Service Mode

    20AR21 20AR31 SERVICE MODE (1) In the Service Mode, Key is used to select the mode in the following oreder. AGC & WHITE POINT GEOMETRIC ADJ. ADJ. MODE MODE MODE OFFSET ADJ. MODE FEATURE OPTION OPTION ADJ. MODE MODE MODE AGC &...
  • Page 9 20AR21 20AR31 OFFSET ADJ. ADJ. MODE MODE Y-D TIME (TV) [ YD ] (DL-TV) ATTENUATE INPUT SIGNAL LEVEL (ATT) Y-D TIME (AV) [ YD ] (DL-AV) VCO FREE RUNNING FREQUENCY ADJ. (VCO) INITIAL/DEFAULT LANGUAGE (INIT) STEREO, SAP, DBX FILTER ADJ. (FILTER)
  • Page 10 20AR21 20AR31 SERVICE MODE DATA SERVICE REMARK ADJUST ITEM POSITION RANGE INITIAL VALUE FIX/ADJ AGC TAKE OVER POINT 0~63 V-LIN VERTICAL SLOPE 0~63 V-AMP VERTICAL AMP 0~63 V-CENT VERTICAL SHIFT 0~63 V-ZOOM VERTICAL ZOOM 0~63 H-CENT HORIZONTAL SHIFT 0~63 H-SIZE...
  • Page 11 0(disable) or1(enable) RGBL RGB BLANK 0(disable) or1(enable) V-CHIP V-CHIP 0(disable) or1(enable) MTS DECODING ENABLED 0(disable) or1(enable) FIX* 20AR21 0/20AR31 1 DEMO DEMO MODE 0(disable) or1(enable) CLOCK REAL TIME CLOCK / ON TIMER 0(disable) or1(enable) must be "1" E-SAVE ENERGY SAVE...

  • Page 12: Service Adjustment

    20AR21 20AR31 Ë SERVICE ADJUSTMENT RF AGC Adjustment 1. Receive a good local channel. 2. Enter the service mode signal category and select the service adjustment "AGC". 3. Set the data value to point where no noise or beat appears.
  • Page 13 20AR21 20AR31 CRT CUT-OFF, BACKGROUND AND SUB-CONTRAST ADJUSTMENT No. Adjusting point Adjusting procedure/conditions Waveform and others CRT CUTOFF 1. Switch TV to VIDEO mode,BLUE BACK OFF, with ADJUSTMENT NO VIDEO signal. 3.5Vdc C BUS 2. Press R/C to set Picture Normal condition.

  • Page 14: Chassis Layout

    20AR21 20AR31 MODEL 20AR21 CHASSIS LAYOUT...
  • Page 15 20AR21 20AR31 MODEL 20AR31 CHASSIS LAYOUT...

  • Page 16: Block Diagram

    20AR21 20AR31 BLOCK DIAGRAM-1...
  • Page 17 20AR21 20AR31 MODEL 20AR21 BLOCK DIAGRAM-2...
  • Page 18 20AR21 20AR31 MODEL 20AR31 BLOCK DIAGRAM-2...

  • Page 19: Description Of Schematic Diagram

    20AR21 20AR31 DESCRIPTION OF SCHEMATIC DIAGRAM WAVEFORM MEASUREMENT CONDITIONS: NOTES: 1. Photographs taken on a standard gated color bar 1. The unit of resistance "ohm" is omitted. signal, the tint setting adjusted for proper color. The (K=k =1000 , M=M ) wave shapes at the red, green and blue cathodes of 2.
  • Page 20 20AR21 20AR31 SCHEMATIC DIAGRAM: CRT Unit (DUNTKA542WEA3)

  • Page 21: Schematic Diagrams

    20AR21 20AR31 MODEL 20AR21 SCHEMATIC DIAGRAM: MAIN Unit (DUNTKA541WEA7)
  • Page 22 20AR21 20AR31 MODEL 20AR31 SCHEMATIC DIAGRAM: MAIN Unit (DUNTKA541WEA8)
  • Page 23 20AR21 20AR31 MODEL 20AR31 SCHEMATIC DIAGRAM: MTS MODULE Unit...

  • Page 24: Printed Wiring Board Assemblies

    20AR21 20AR31 PRINTED WIRING BOARD ASSEMBLIES PWB-A: MAIN Unit (Wiring Side)
  • Page 25 20AR21 20AR31 PWB-A: MAIN Unit (Chip Parts Side)
  • Page 26 20AR21 20AR31 PWB-B: CRT Unit (Wiring Side) PWB-B: CRT Unit (Chip Parts Side)
  • Page 27 20AR21 20AR31 PWB-E: MTS MODULE Unit (Wiring Side) PWB-E: MTS MODULE Unit (Chip Parts Side)

  • Page 28: Replacement Parts List

    AD100419 RH-EX0627GEZZ D532 Zener Diode, 8.2V AD100412 RH-DX0475CEZZ D601 Diode AD100505 VHD1SS244//-1 D602 Diode PWB-A DUNTKA541WEA7 – MAIN Unit (20AR21) — å AD 100422 RH-EX0667GEZZ D603 Zener Diode, 27V PWB-A DUNTKA541WEA8 – MAIN Unit (20AR31) — å AD100406 RH-DX0131CEZZ D606 Diode PWB-B DUNTKA542WEA1 –...
  • Page 29 å AD100497 VCKYPH3DB561K C752 560p 2000V Ceramic AD100453 VCEA0A1CW107M C252 å AD100389 RC-EZ0724CEZZ C753 AD100458 VCEA0A1CW477M C301 470 16V EL. (20AR21) å AD100388 RC-EZ0638CEZZ C754 160V EL. AD100393 RC-EZA009WJZZ C301 220 16V EL. (20AR31) å AD100454 VCEA0A1CW108M C755 1000 16V...
  • Page 30 20AR21 20AR31 Toshiba Part No. Part No. Ref.No. Description Toshiba Part No. Part No. Ref.No. Description PWB-A: DUNTK541WEA7 (20AR21) AD100572 VRS-CY1JF392J R209 3.9k 1/16W M-Ox. PWB-A: DUNTK541WEA8 (20AR31) AD100589 VRS-RG3LB223J R216 22k 3W M-Ox. AD100526 VRD-RA2BE392J R219 3.9k 1/8W Carbon...
  • Page 31 220 1/16W M-Ox. AD100367 QJAKE0210CE02 J404 Jack, Audio (R)(AV) AD100563 VRS-CY1JF221J R803 220 1/16W M-Ox. (20AR31) AD100563 VRS-CY1JF221J R804 220 1/16W M-Ox. AD100372 QJAKF0074CEZZ J409 Jack, Rear AV (20AR21) AD100583 VRS-CY1JF822J R805 8.2k 1/16W M-Ox. AD100373 QJAKG0093CEZZ J409 Jack, Rear AV (20AR31)

  • Page 32: Crt Unit

    20AR21 20AR31 Toshiba Part No. Part No. Ref.No. Description Toshiba Part No. Part No. Ref.No. Description PWB-A: DUNTK541WEA7 (20AR21) PWB-B: DUNTK542WEA3 PWB-A: DUNTK541WEA8 (20AR31) CRT UNIT MAIN UNIT (Continued) TRANSISTORS AD100379 QPLGN0461CEZZ P302 Plug, 4-pin (S) AD100381 QPLGN0660CEZZ P601 Plug, 6-pin (K)
  • Page 33 20AR21 20AR31 Toshiba Part No. Part No. Ref.No. Description PWB-E: DUNTK545WEA0 (20AR31) MTS MODULE UNIT INTEGRATED CIRCUITS AD100507 VHiCXA2074Q-1 IC3001 CXA2074Q AD100508 VHiMM1501XN-1 IC3002 MM1501XNRE TRANSISTORS AD100595 VS2SC3198-G-1 Q3003 C3198-G DIODE AD100420 RH-EX0632GEZZ D3001 Zener Diode CAPACITORS [EL. …Electrolytic] AD100447...

  • Page 34: Packing Parts

    Toshiba Part No. Part No. Ref.No. Description PACKING PARTS MISCELLANEOUS PARTS (NOT REPLACEMANT ITEM) AD100359 QACCZ3008PEZZ ACC701 AC Cord AD100436 SPAKC0242GJZZ – Packing Case (20AR21) — å AD100600 VSP9050PB40YA SP301 Speaker (R)(20AR21) AD100436 SPAKC0242GJZZ – Packing Case (20AR21) — AD100600 VSP9050PB40YA...

  • Page 35: Packing Of The Set

    20AR21 20AR31 PACKING OF THE SET Polyethylene Bag Operation Manual Infrared R/C Unit Batteries Wrapping Paper Buffer Material FRONT Packing Case Use tape to fix top side of pack case. REAR Use 12 staples fix the packing case. MARK : Not Replacement Items.
  • Page 36 TOSHIBA CORPORATION 1-1, SHIBAURA 1-CHOME, MINATO-KU, TOKYO 105-8001, JAPAN...

This manual is also suitable for:

20ar31

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